[SpookyCharlie]

Hello. I have a few questions that I'm having difficulty with regarding moon regolith.

I was looking at the composition of lunar regolith (http://articles.adsabs.harvard.edu//full/1975lspa.book.....T/0000064.000.html) and saw that on average, it is composed of about 12% calcium oxide. If I were to pour a sample of regolith into water, would I get an exothermic reaction? And if so, at what ratio?

The other chemicals composing the regolith are Silica (45%), Alumina (15%), Iron Oxide (14%), Magnesia (9%), Titanuim Oxide (4%) and Sodium Oxide (0.6%). I'm not sure how these chemicals would interact with water, more specifically, if any of these other chemicals would diminish or restrict the reaction of the lime and water. Or increase it.

If I were on the moon and I poured lunar regolith/soil into glass globes filled with water, might there be enough energy released to expand the contents of the globe significantly enough to break the glass? Ratio? How much would boiling water increase the reaction's volatility?

Thanks much,
Ryan

[Borek]

Giving mineral composition as oxides is quite popular between geologists.

Calcium silicate CaSiO₃ can be reported as CaO·SiO₂ - so technically it contains 48.3% CaO, but it won't react with water.

[Arkcon]

Hello. I have a few questions that I'm having difficulty with regarding moon regolith.

I was looking at the composition of lunar regolith (http://articles.adsabs.harvard.edu//full/1975lspa.book.....T/0000064.000.html) and saw that on average, it is composed of about 12% calcium oxide.

I didn't check your reference, but, generally, since the moon is airless and waterless, reduced compounds do accumulate.  http://en.wikipedia.org/wiki/Lunar_regolith#Mineralogy_and_composition  So yes, this part is true.  Unless the reference is just using that as a common shorthand for relative composition, that is done a lot, even for Earth samples that don't have CaO free, just a warning.
{EDIT} This is what Borek: is talking about.

If I were to pour a sample of regolith into water, would I get an exothermic reaction?

 

You can get an exothermic reaction with samples of CaO on Earth, so yes.

And if so, at what ratio?

I don't really see how ratios follow directly from your last question, maybe you can tell us more of what you mean?

The other chemicals composing the regolith are Silica (45%), Alumina (15%), Iron Oxide (14%), Magnesia (9%), Titanuim Oxide (4%) and Sodium Oxide (0.6%). I'm not sure how these chemicals would interact with water, more specifically, if any of these other chemicals would diminish or restrict the reaction of the lime and water. Or increase it.

These also exist on Earth, and have defined properties.  You can look each up individually.  Again, these may be present, or the oxides may be listed just as a short hand way of listing elements. {EDIT} Again, like Borek: said.

If I were on the moon and I poured lunar regolith/soil into glass globes filled with water, might there be enough energy released to expand the contents of the globe significantly enough to break the glass?

That's a pretty open ended question.  How big and how strong the glass vessel is determines its bursting strength.  This is less easy to look up.  The energy released is possible to calculate.

Ratio?

Hmmm.  Again, you've come up with a very far-fetched idea, and want us to know the ratios -- of what?  I would suggest you mix the reactants stoichiometrically, using a balanced equation for your known reactants.  This is a common beginner problem in chemistry courses.  Why not try to figure this part out here on this forum, with a few more postings?  You're not getting to the Moon any time soon, so your original question can wait.

How much would boiling water increase the reaction's volatility?

By how much energy is in boiling water.  This is also something you can calculate.  N.B. -- you only get out energy you put in (usually less) and putting energy into water to boil it can get expensive.

Thanks much,
Ryan

Shine on you crazy diamond.

[SpookyCharlie]

Thank you very much for the quick responses everyone. I've never posted on a science forum, I just read them a lot when "researching" stories and basically every time I don't understand something. As you can see from the phrasing of my question, I am severely lacking in my chemistry understanding.

For those of you who wanted more info...

I am writing a sci-fi alternate-history story that is set in the 40s that has the feel of an old pulp story. I'm taking it to a different level as a musician and I'm turning the story into an album on which I alternate between songs and scenes with character voices and sound design—attempting to recreate the feel of a 40s/50s radio drama. But I want to inject at least a decent bit of honest science, since I'll be stretching some truths/facts...I mean, it is pulp fiction.

So, an American astronaut is hastily launched upward in a sort of steam-punk vessel in response to German activity. On the moon, the astronaut finds some creatures he calls "shadow people". The long and short has him trying to save these creatures from the Nazi automatons that he also discovers on the moon. These machines are like big metal crab-spiders with a large glass sphere "abdomen" filled with water. As you might imagine, they are steam powered. From what I’ve read, the regular day-time temperature around the equator is above water’s boiling point (about 242 F) so they must stay in the sunlight near the equatorial region. Being automatons, they are fairly limited in function. Basically they roam in preceding ellipses, like an old spirograph, grinding and gathering any rocks in their paths.

The point of my original question was to help me decide what method the hero will use to destroy these robo-Nazis. One idea, Plan A, the one I’m trying to figure out right now, hinges on lunar regolith’s reactiveness with water. I’m thinking there is a one-way cork/seal on the glass sphere housing the automatons’ water. I suppose things don’t need to be exact (ratio of regolith to water and exact thickness of glass containers), I just want a concept that is realistic enough to be possible. Then the hero stuffs a bunch of regolith into the glass containers and the automatons start cracking and losing water or even blowing open, shattering the glass globe.

Or maybe the hero has the ability to separate the chemical contents of the regolith in order to stuff pure calcium oxide into the globes for a better reaction. In this case, I’d need to know how someone might go about deriving the calcium oxide from the rest of the regolith in the 40s. Or even 50s. I can stretch the time period a bit.

This destruction of the automatons is more fantastical and impressive, so I want to try and figure this out. However, I have a Plan B: deadfalls. The hero and the shadow people dig out some trenches/deadfalls and the automatons fall in. With the temperatures in craters and basically any shadowed area on the moon being insanely cold, the steam-powered automatons aren’t going anywhere.

Plan C involves covering the automatons in lunar dust due to its reflective properties. I’ve read that just a couple of centimeters below the top level of regolith is also insanely cold. So, Plan C would also do the trick. But again, not as fantastic as Plan A.

Thanks for the continued help.

Ryan
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